Still reeling from plague and civil war, the Winter Kingdoms face an invasion force from across the Northern Sea led by a dark spirit mage in the name of ancient, vanquished gods. Summoner-King Martris Drayke and an untested generation of new rulers must stand against an unholy alliance of shadowy invaders. To prevail, Tris must win the uncertain support of the Dread, spirit-beings that stand guard within the sacred barrows over an even more fearsome threat imprisoned within. In the balance lies not only the freedom of the Winter Kingdoms but Tris's life and the soul of his young son, whose untested magic might be the biggest spoil of war.